It is well known in the art that the conventional methods to get clean steel employ electroslag furnace remelting technology. The copper water-cooled crystallizer is filled with molten slag, in which inserted one end of the consumable electrode. The consumable electrode, slag pool, metal bath, steel ingot together with the bottom water tank form a loop through a short-net wire and transformer. During the power-on process, the Joule heat released from the slag pool gradually melt the end of the consumable electrode, and then the droplets converged from the molten metal pass through the slag pool and fall into the crystallizer to form a metal bath, which then rapidly solidifies into steel ingot after being cooled by water. During the forming of electrode tip droplets and droplets dripping through the slag pool, the steel fully contacts with the slag, and the non-metallic inclusion is absorbed by the slag.
The harmful elements in steel (e.g. sulfur, lead, antimony, bismuth, tin) was effectively removed through a reaction between steel and slag and a high-temperature gasification, but the remelting of ingot consumes a good deal of energy, and also restricts the large-scale industrial production. Moreover, the slag charge contains a lot of calcium fluoride which can pollute the environment. So, a de-dust and a de-fluorine device are have to be arranged. In addition, because the efficiency is particularly low, especially the electric arc could seriously damage the crystallizer, a crystallizer mold in the manner of electroslag furnace remelting can only refine scores of furnace of steel, which increases the cost of production. However, the ordinary ingot casting method can not achieve the effect of cleanliness.